Aortoiliac disease: two-dimensional inflow MR angiography with lipid suppression

A magnetic resonance (MR) imaging strategy, SLIP (spatially separated lipid presaturation), which can be incorporated into existing MR imaging and MR angiographic techniques, has been developed to suppress lipid signal. The authors report the clinical application of this technique, with a triple comparison of two-dimensional inflow MR angiography, with and without SLIP, and x-ray angiography in patients with aortoiliac disease. SLIP improved visualization of arterial segments, with 50 of 63 (79%) arterial segments visualized versus 41 of 63 (65%) for non-SLIP MR angiography. The SLIP strategy aids in the depiction of slow or turbulent flow, because the lipid signal is suppressed while the intravascular signal is left undisturbed. Image quality improves because of the combination of decreased background lipid signal intensity and use of the maximum-intensity-projection algorithm. Compared with x-ray arteriography, non-SLIP MR angiography had a sensitivity and specificity of 60% and 56%, respectively, for detection of lesions with 50%-100% diameter reduction, while SLIP MR angiography had a sensitivity and specificity, respectively, of 53% and 67%.